Effects of rumen undegradable protein levels in pre- and post-partum diets on performance, metabolism, and biomarkers of inflammation of dairy cows during the transition period

• Grant number: 22/00789-2
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2022
• End date: April 30, 2024
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Francisco Palma Rennó
• Grantee: Francisco Palma Rennó
• Host Institution: Faculdade de Medicina Veterinária e Zootecnia (FMVZ). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The transition period is extremely challenging in the productive cycle of dairy cows, where a carefully diet formulation may improve performance of subsequent lactation as well as animal health. Among challenges for a successful adaptation during this period is a reduction in dry matter (DM) intake. The feed intake decreases from 30 to 35% during the last 3 wks before parturition, whereas 89% of the decrease in intake occurs during the last 7 days before parturition. The relatively low DM intake during the transition period may jeopardize metabolizable protein (MP) supply in the small intestine causing a negative balance of protein and essential amino acids. A considerable volume of studies evaluated the effects of protein supplementation during the pre-partum on performance and health of transition cows. However, most of studies flawed to generate promising results on performance during the post-period. The first reason for unsuccess of productive responses in the post-partum is using crude protein (CP) to express requirements of protein. Others include - decrease the rumen degradable protein (RDP) to increase the level of rumen undegradable protein (RUP), which reduces microbial protein synthesis resulting in no improvements in intestinal supply of MP, the utilization of diets with high protein content during the post-partum period hiding the effects of inadequate supply of protein during the pre-partum period, or any combination of the previous reasons. Another challenge of evaluating responses to RUP supply during the pre-partum period is the amino acid balancing. Few studies described the amino acid profile of diets and whether these amino acids were absorbed in the intestinal, in other words, previous studies did not determine the amino acid profile of feeds and blood of cows. Literature lacks information on the interaction between RUP levels in pre- and post-partum diets. The objective of this study is to evaluated the effects of different RUP dietary levels in pre- and post-partum periods on nutrient intake and apparent digestibility, microbial protein synthesis, blood metabolites, amino acid profile in blood, blood biomarkers of inflammation, and milk yield and composition. (AU)